Traditional display technology relates to glass plate displays which cannot be bent at will. It is a trend for display technology in the future that displaying a massive amount of information on a flexible body, i.e., a flexible display, is desired. Current display techniques capable of achieving flexible display include LCD (Liquid Crystal Display), OLED (Organic Light-emitting Diode), EPD (Electronic Paper Display), PDLC (Polymer Dispersed Liquid Crystal), and CHLC (Cholesteric Liquid Crystal) modes. The underlying substrates mainly include ultra-thin glass, metal foils, and plastics.
Ultra-thin glass substrates boast good vapor and oxygen obstructing properties and excellent transparency, but they are sensitive to crack defects and hence have a poor performance in terms of impact resistance and bending properties. Therefore, it is difficult to perform a roll-to-roll process to develop ultra-thin bendable glass.
Being resistant to a high temperature and being low in cost, metal foil substrates have the function of obstructing vapor and oxygen. As the metal foil substrates per se exhibit good ductility, it is easy to perform a roll-to-roll process. However, due to a comparatively large surface roughness of the foils (Ra=0.6 μm), it is still necessary to plate a planarization layer after polishing, which increases the thickness of the device and, in turn, exerts an adverse influence on characteristics of the associated TFT (Thin Film Transistor).
Plastic substrates are very promising materials for flexible displays with better flexibility, a lighter weight, and better impact resistance. In the fabrication process, plastic is usually attached to a glass substrate, which is then subjected to operations such as array process, organic EL (electroluminescent) evaporation process, encapsulation, and IC bonding. Then, the plastic is stripped from the glass substrate. A conventional mechanical stripping method is shown in FIG. 1. In this method, a plastic film 2 is removed (i.e., wound off) by a roller 1. Since there is an adhesion layer which has a certain bonding force at the contact interface between the plastic material and a glass substrate 3, small gaps may turn up between the plastic film 2 and the lower surface of the roller 1 during winding, and consequently the plastic will be bent at a small angle, resulting in micro-cracks in the layered structure on the upper surface of the plastic film, which could influence the performance of the device, lead to a separation between layers, or possibly even a failure of the device.